Question: Simplify the following expression: $12\sqrt{63}$.
Solution: First, try to factor a perfect square out of the radical. $= 12\sqrt{63}$ $= 12\sqrt{9 \cdot 7}$ Separate the radical and simplify. $= 12\sqrt{9} \cdot \sqrt{7}$ $= 12 \cdot 3 \cdot \sqrt{7}$ $= 36\sqrt{7}$